Why am I reminded of the days when Scotchguard showed up on the market?

I can certainly see its utility, but I just can't seem to envision myself sleeping in a tent sprayed with this stuff, or sporting a jacket "field applied" with it. I just get the feeling like this is one of those "too good to be true" things, and it will eventually be recalled for something toxic-related. (Lest we forget "Bisphenol A"?)

From what I can tell, this product works by trapping a film of air at the surface, with the water sitting on top of the air. The nano-scale details are the secret. This works OK for low-pressure water hitting the surface.

It will not work against high pressure water, against abrasion, or on a soft fabric. When you combine a soft fabric with rubbing against wet scrub you are going to get very rapid wetting through.